Motor rotor and motor

Abstract

The invention discloses a motor rotor and a motor, and the motor rotor comprises a rotor core, the rotor core is provided with a plurality of first magnetic steel grooves which are uniformly distributed in the circumferential direction of the rotor core, the first magnetic steel grooves extend in the radial direction, and main permanent magnets which are magnetized in the tangential direction are arranged in the first magnetic steel grooves; a second magnetic steel groove is further formed between any two adjacent first magnetic steel grooves in the rotor core, an auxiliary permanent magnet module is arranged in the second magnetic steel groove, the auxiliary permanent magnet module comprises at least two first auxiliary permanent magnet units, and the magnetic poles of the closest surfaces of any two adjacent main permanent magnets are the same; the magnetizing direction of the first auxiliary permanent magnet unit comprises a radial magnetizing component; the magnetizing direction of the first auxiliary permanent magnet unit comprises a tangential magnetizing component, and the tangential magnetizing component of the first auxiliary permanent magnet unit is the same as the magnetizing direction of the main permanent magnet close to the first auxiliary permanent magnet unit.

Description

Motor rotor and motor

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 30, 2023, with application number 202310797571.1 and invention name “Motor Rotor and Motor”, the entire contents of which are incorporated by reference into the application. Technical Field

[0002] The present application relates to the field of motor technology, and in particular to a motor rotor and a motor. Background Art

[0003] Permanent magnet motors are used as actuators in industrial servo systems due to their high dynamic response capability, high power density, high control accuracy and other advantages. They receive position, speed and torque instructions from the host computer and accurately drive the load. They have strong overload capacity, good linearity and fast dynamic response, and are therefore widely used in the industrial field.

[0004] With the development of industry, various applications have placed higher demands on the power density and torque density of industrial motors. However, in traditional strip-type internal permanent magnet motors, there is a lot of leakage flux near the internal shaft surface of the rotor, resulting in a decrease in the motor's back EMF and power density. Technical issues

[0005] The main purpose of this application is to provide a motor rotor and a motor, aiming to solve the problem that traditional strip-type motors have a lot of leakage magnetic field inside the rotor core near the shaft surface, which leads to a decrease in back electromotive force and power density, thereby improving the torque and power density of the motor and reducing torque fluctuations. Technical Solutions

[0006] To achieve the above-mentioned object, the present application proposes a motor rotor, which includes a rotor core, wherein the rotor core has a plurality of first magnetic steel slots uniformly distributed along the circumference of the rotor core, the first magnetic steel slots extending radially and provided with tangentially magnetized main permanent magnets; a second magnetic steel slot is further provided between any two adjacent first magnetic steel slots on the rotor core, an auxiliary permanent magnet module is provided in the second magnetic steel slot, the auxiliary permanent magnet module includes at least two first auxiliary permanent magnet units, and the closest surface magnetic poles of any two adjacent main permanent magnets are the same; the magnetization direction of the first auxiliary permanent magnet unit includes a radial magnetization component; the two first auxiliary permanent magnet units located in opposite magnetization directions are provided with a second magnetic steel slot. The direction of the radial magnetization component of the first auxiliary permanent magnet unit between the main permanent magnets points to the stator along the radial direction of the rotor core; the direction of the radial magnetization component of the first auxiliary permanent magnet unit located between two main permanent magnets with opposite magnetization directions points to the rotor shaft along the radial direction of the rotor core; the magnetization direction of the first auxiliary permanent magnet unit includes a tangential magnetization component, and the tangential magnetization component of the first auxiliary permanent magnet unit is the same as the magnetization direction of the main permanent magnet close to the first auxiliary permanent magnet unit, wherein the magnetization direction of the main permanent magnet and the tangential magnetization direction of the first auxiliary permanent magnet unit are both tangential directions of a circle with the axis of the rotor core as the center.

[0007] In one embodiment of the present application, the at least two first auxiliary permanent magnet units include at least two auxiliary permanent magnets having at least one magnetization direction or one auxiliary permanent magnet having at least two magnetization directions.

[0008] In one embodiment of the present application, the angle between all magnetizing directions / the opposite directions of the magnetizing directions in the auxiliary permanent magnet module and the center line of the second magnetic steel slot along the radial direction of the rotor core is α; wherein 0°≤α≤90°.

[0009] In one embodiment of the present application, the angle between all magnetizing directions / the opposite directions of the magnetizing directions in the auxiliary permanent magnet module and the center line of the second magnetic steel slot along the radial direction of the rotor core is α; wherein 0°≤α≤40°.

[0010] In one embodiment of the present application, the distribution of the auxiliary permanent magnet modules is symmetrical about the radial center line of the rotor core along the second magnetic steel slot, and the angle α of each of the first auxiliary permanent magnet units located on one side of the center line decreases successively from the side away from the center line to the side close to the center line.

[0011] In one embodiment of the present application, the auxiliary permanent magnet module further includes a second auxiliary permanent magnet unit located in the middle of the first auxiliary permanent magnet unit, and the angle α between the magnetization direction of the second auxiliary permanent magnet unit and the center line of the second magnetic steel slot along the radial direction of the rotor core is 0.

[0012] In one embodiment of the present application, the auxiliary permanent magnet module is disposed close to the inner edge of the rotor core.

[0013] In one embodiment of the present application, the side wall of the auxiliary permanent magnet module close to the inner edge of the rotor core and the side wall of the main permanent magnet close to the inner edge of the rotor core are located on the same circumference with the axis of the rotor core as the center.

[0014] In one embodiment of the present application, the length of the auxiliary permanent magnet module along the radial direction of the rotor core is L2, and the length of the main permanent magnet along the radial direction of the rotor core is L1, wherein 0<L2 / L1<1.

[0015] In one embodiment of the present application, 0.1≤L2 / L1≤0.5.

[0016] In one embodiment of the present application, in the adjacent main permanent magnet and auxiliary permanent magnet modules, a side surface of the main permanent magnet facing the auxiliary permanent magnet module and a side surface of the auxiliary permanent magnet facing the main permanent magnet module are parallel or closely attached.

[0017] In one embodiment of the present application, a distance between a side surface of the main permanent magnet facing the auxiliary permanent magnet module and a side surface of the auxiliary permanent magnet module facing the main permanent magnet is D, and 0≤D≤0.5 mm.

[0018] In one embodiment of the present application, the rotor core includes a plurality of stacked first silicon steel sheets, and the main permanent magnet and the auxiliary permanent magnet module both pass through the first silicon steel sheets;

[0019] And / or, the rotor core includes a plurality of stacked first silicon steel sheets, with at least one second silicon steel sheet stacked between at least two adjacent first silicon steel sheets; the main permanent magnet and the auxiliary permanent magnet module both pass through the first silicon steel sheet and the second silicon steel sheet, and the second silicon steel sheet has a hollow portion, and the main permanent magnet and the auxiliary permanent magnet module are at least partially located in the hollow portion.

[0020] In addition, the present application also provides a motor, which includes a stator assembly and the motor rotor as described above, wherein the stator assembly is sleeved on the periphery of the motor rotor. Beneficial effects

[0021] In the technical solution of the present application, the motor rotor is applied to the motor. The rotor and the motor of the present application are provided by adding an auxiliary permanent magnet module between two adjacent main permanent magnets. The auxiliary permanent magnet module includes at least two first auxiliary permanent magnet units. The auxiliary permanent magnet module cooperates with the main permanent magnet. On the one hand, the auxiliary permanent magnet module reduces magnetic leakage on the inner surface of the rotor core and the outer surface of the rotor shaft. On the other hand, the auxiliary permanent magnet module is also located in the main magnetic circuit, which can further enhance the magnetic flux linkage on the main magnetic circuit and the magnetic density in the air gap, thereby enhancing the magnetic concentration ability and improving the torque and power density of the motor. At the same time, the magnetization direction of the auxiliary permanent magnet module can form a more sinusoidal air gap magnetic field in the air gap, thereby reducing the air gap magnetic density harmonics and the opposite electromotive force harmonics, and ultimately reducing the cogging torque and torque fluctuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0023] FIG1 is a schematic structural diagram of a motor rotor in an embodiment of the present application;

[0024] FIG2 is a schematic diagram of a partial structure of a motor rotor in an embodiment of the present application;

[0025] FIG3 is a schematic structural diagram of a motor rotor in another embodiment of the present application;

[0026] FIG4 is a schematic structural diagram of a motor rotor in another embodiment of the present application;

[0027] FIG5 is a schematic structural diagram of a rotor core according to an embodiment of the present application;

[0028] FIG6 is a schematic structural diagram of a first silicon steel sheet in an embodiment of the present application;

[0029] FIG7 is a schematic structural diagram of a second silicon steel sheet in an embodiment of the present application;

[0030] FIG8 is a schematic structural diagram of a motor in an embodiment of the present application;

[0031] FIG9 is a comparison diagram of the absolute value of the core magnetic flux density of the topology of the combination of the main magnet and the auxiliary permanent magnet module in the embodiment of the present application and the traditional banner topology at a vertical distance of 1 mm from the side of the first magnetic steel slot and the second magnetic steel slot close to the rotor shaft;

[0032] FIG10 is a graph showing the relationship between the angle α between the magnetizing direction of the auxiliary permanent magnet module and the radial center line of the second magnetic steel slot along the rotor core and the torque performance of the motor in an embodiment of the present application.

[0033] Description of Figure Numbers:

[0034] Reference numerals Name Reference numerals Name 100 Motor rotor 143 Second limiting groove 1 Rotor core 15 Mounting hole 11 First magnetic steel groove 16 Groove 12 Second magnetic steel groove 2 Main permanent magnet 13 First silicon steel sheet 3 Auxiliary permanent magnet module 131 First through-slot 31, 32, 33, 34, 311, 312, 314, 315, 316, 317 First auxiliary permanent magnet unit 132 Second through-slot 313 Second auxiliary permanent magnet unit 14 Second silicon steel sheet 200 Motor 141 Hollow portion 201 Stator assembly 142 First limiting groove 202 Air gap

[0035] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. Modes for Carrying Out the Invention

[0036] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0037] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0038] In addition, the terms "first," "second," and so on, used in this application are for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0039] In this application, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0041] The present application proposes a motor rotor, which aims to solve the problem of a large amount of leakage magnetic field on the internal shaft surface of the rotor, resulting in a decrease in back electromotive force and power density, thereby improving the torque and power density of the motor.

[0042] As shown in Figures 1 to 5, in one embodiment of the present application, a motor rotor 100 includes a rotor core 1 having a plurality of first magnetic steel slots 11 uniformly distributed along the circumference of the rotor core 1. The first magnetic steel slots 11 extend radially and contain tangentially magnetized main permanent magnets 2. A second magnetic steel slot 12 is provided between any two adjacent first magnetic steel slots 11 in the rotor core 1. An auxiliary permanent magnet module 3 is disposed within the second magnetic steel slot 12. The auxiliary permanent magnet module 3 contains at least two first auxiliary permanent magnet units. For example, in Figure 1, one auxiliary permanent magnet module 3 contains two first auxiliary permanent magnet units 31 and 32, while another auxiliary permanent magnet module 3 contains two first auxiliary permanent magnet units 33 and 34. It is understood that the number n of the at least two first auxiliary permanent magnet units can be 2, 3, 4, ..., where n is an integer. In one embodiment of the present application, the at least two first auxiliary permanent magnet units include at least two auxiliary permanent magnets having at least one magnetization direction or one auxiliary permanent magnet having at least two magnetization directions.

[0043] In the embodiment of the present application, the at least two first auxiliary permanent magnet units can be understood as including at least two auxiliary permanent magnets, each auxiliary permanent magnet having at least one magnetizing direction, and each auxiliary permanent magnet forming an auxiliary permanent magnet unit. The at least two first auxiliary permanent magnet units can also be understood as including one auxiliary permanent magnet, in which case the auxiliary permanent magnet has at least two magnetizing directions, i.e., one magnetizing direction constitutes one auxiliary permanent magnet unit. In other words, the auxiliary permanent magnet module to which the at least two first auxiliary permanent magnet units belong is integrally formed, and at least two magnetizing directions are formed on the integrally formed auxiliary permanent magnet module. The embodiment of the present application does not limit the form of the auxiliary permanent magnet unit, as long as it can form at least two magnetizing directions.

[0044] In the embodiment of the present application, the number of the second magnetic steel slots 12 located between the two main permanent magnets 2 can be one or two or more. When the number of the second magnetic steel slots 12 is one, at least two first auxiliary permanent magnet units are set in the one second magnetic steel slot 12. When the number of the second magnetic steel slots 12 is two, one, two or more first auxiliary permanent magnet units can be set in each second magnetic steel slot 12, and the number of first auxiliary permanent magnet units set in the two second magnetic steel slots 12 can be different. Deformably, when the number of the second magnetic steel slots 12 is multiple, one, two or more first auxiliary permanent magnet units can be set in each second magnetic steel slot 12, and the number of first auxiliary permanent magnet units set in the multiple second magnetic steel slots 12 can be different. In other words, the embodiment of the present application does not limit the number of second magnetic steel slots, as long as at least two first auxiliary permanent magnet units can be set.

[0045] In this embodiment, the motor rotor 100 is applied to the motor shown in Figure 8. Due to the presence of the auxiliary permanent magnet module 3, the magnetic flux density in the rotor core 1 between the main permanent magnet 2 and the rotor shaft is reduced compared to the traditional banner-type built-in permanent magnet motor. Therefore, the leakage flux is reduced, the utilization rate of the permanent magnet is improved, and it is helpful to improve the torque and power density of the motor. The present application adds an auxiliary permanent magnet module 3 between two adjacent main permanent magnets 2 to cooperate with the main permanent magnet 2. On the one hand, the auxiliary permanent magnet module 3 is used to reduce the leakage flux on the inner surface of the rotor core 1 and the outer surface of the rotor shaft; on the other hand, the auxiliary permanent magnet module 3 is still in the main magnetic circuit, which can further enhance the magnetic flux on the main magnetic circuit and the magnetic flux density in the air gap 202, thereby enhancing the magnetic concentration ability and improving the torque and power density of the motor.

[0046] In one embodiment, the closest surface magnetic poles of any two adjacent main permanent magnets 2 are identical. That is, among three consecutively adjacent main permanent magnets 2, the north pole of the middle main permanent magnet 2 faces the north pole of the main permanent magnet 2 on its side, and the south pole of the middle main permanent magnet 2 faces the south pole of the main permanent magnet 2 on its other side. Furthermore, by installing an even number of main permanent magnets 2 in evenly distributed first magnetic steel slots 11, the forces acting on the main permanent magnets 2 are balanced, ensuring that the number of poles in the motor 200 is equal to the number of main permanent magnets 2.

[0047] As shown in FIG1 , the auxiliary permanent magnet module 3 includes at least two first auxiliary permanent magnet units 31, 32, 33, and 34. The magnetization directions of the at least two first auxiliary permanent magnet units 31, 32, 33, and 34 are determined by the directions of the main permanent magnets 2 on either side. In this embodiment, the direction near the rotor axis is considered inner, and the direction near the air gap 202 is considered outer. The magnetization directions of the first auxiliary permanent magnet units 31, 32, 33, and 34 all have a radial magnetization component. The radial magnetization components of the two first auxiliary permanent magnet units 31 and 32 located between two main permanent magnets 2 with opposite magnetization directions are directed radially outward along the rotor core 1. Specifically, the radial magnetization components are directed radially toward the stator assembly 201 along the rotor core 2. The radial magnetization components of the two first auxiliary permanent magnet units 33 and 34 located between two main permanent magnets 2 with opposite magnetization directions are directed radially inward along the rotor core 1. Specifically, the radial magnetization components are directed radially toward the rotor axis along the rotor core 1. Specifically, the radial magnetization components of the two first auxiliary permanent magnet units 31 and 32 located between the main permanent magnet's north poles are directed radially toward the stator assembly 201, while the radial magnetization components of the two first auxiliary permanent magnet units 33 and 34 located within the main permanent magnet's south poles are directed radially toward the rotor core 1 and toward the rotor axis. In other words, the magnetization direction of the main permanent magnets 2 alternates between adjacent poles. When the magnetization directions of two adjacent main permanent magnets 2 are opposite, the direct-axis flux density and flux linkage direction radially point from the rotor to the stator, while the magnetization direction of the two first auxiliary permanent magnet units 31 and 32 located in the middle includes a component radially toward the stator. Conversely, when the magnetization directions of two adjacent main permanent magnets 2 are opposite, the magnetization direction of the first auxiliary permanent magnet units 33 and 34 located in the middle includes a component radially from the rotor toward the rotor axis. This strengthens the direct-axis flux linkage and the flux density of the main magnetic circuit, ultimately enhancing the magnetic flux concentration capability of the motor rotor 100.

[0048] Based on the above embodiment, the magnetization direction of each first auxiliary permanent magnet unit 31, 32, 33, 34 has a tangential magnetization component. The tangential magnetization component of the first auxiliary permanent magnet units 31, 32, 33, 34 is the same as the magnetization direction of the main permanent magnet 2 adjacent to the first auxiliary permanent magnet units 31, 32. The magnetization direction of the main permanent magnet 2 and the tangential magnetization direction of the first auxiliary permanent magnet units 31, 32, 33, 34 are both tangential to a circle centered on the axis of the rotor core 1. This allows for a more sinusoidal air gap magnetic field to be formed in the air gap 202, thereby reducing magnetic flux density harmonics and back electromotive force harmonics in the air gap 202, ultimately reducing cogging torque and torque ripple.

[0049] Specifically, when the main permanent magnet 2 is magnetized clockwise, the tangential magnetization components of the first auxiliary permanent magnet units 31 and 33 located on either side of the main permanent magnet 2 are also directed clockwise. When the main permanent magnet 2 is magnetized counterclockwise, the tangential magnetization components of the two first auxiliary permanent magnet units 32 and 34 located on either side of the permanent magnet 2 are also directed counterclockwise. The main permanent magnet 2 and the auxiliary permanent magnet module 3 form a quasi-Halbach array, increasing the magnetic field on the air gap 202 side and reducing the magnetic field on the rotor shaft side. This further optimizes torque ripple performance by varying the magnetization angles of at least two first auxiliary permanent magnet units 31.

[0050] Since the inner magnetic field of the ideal Halbach array is a standard zero magnetic field, and the auxiliary permanent magnet module 3 and the main permanent magnet 2 in the embodiment of the present application form a quasi-Halbach array, the magnetic flux density of the inner edge of the rotor core 1 is reduced. Compared with the traditional banner-type internal permanent magnet motor, the leakage flux on the inner side of the rotor core is greatly reduced, the effective utilization rate of the flux is increased, and it helps to increase the power density.

[0051] In one embodiment, the angle between all magnetizing directions / the opposite direction of the magnetizing direction in each auxiliary permanent magnet module 3 and the center line of the second magnetic steel slot along the radial direction of the rotor core is α. Specifically, the angle between all magnetizing directions of the auxiliary permanent magnet module 3 located between two main permanent magnets with opposite magnetizing directions (between the north poles of the main permanent magnets) and the center line of the second magnetic steel slot along the radial direction of the rotor core is α. When the angle between all magnetizing directions of the auxiliary permanent magnet module located between two main permanent magnets with opposite magnetizing directions (between the north poles of the main permanent magnets) and the center line of the second magnetic steel slot along the radial direction of the rotor core is α, 0°≤α≤90°.

[0052] Specifically, using Figure 1 as an example, the magnetization direction of the first auxiliary permanent magnet units 31 and 32, located between two main permanent magnets with opposing magnetization directions (between the north poles of the main permanent magnets), forms an angle α with the centerline A of the second magnetic slot along the radial direction of the rotor core. The opposite magnetization direction of the first auxiliary permanent magnet units 33 and 34, located between two main permanent magnets with opposing magnetization directions (between the south poles of the main permanent magnets), also forms an angle α with the centerline A of the second magnetic slot along the radial direction of the rotor core. When the angle α varies between 0° and 90°, the motor's torque performance, including average torque and torque ripple, also changes accordingly. The average torque decreases with increasing angle α, while the torque ripple first decreases and then increases. Therefore, the angle α can be optimized to achieve a corresponding design solution based on torque performance requirements.

[0053] In the example of the first embodiment described above, the angle α between all magnetizing directions / opposite magnetizing directions within the auxiliary permanent magnet module 3 and the radial centerline A of the second magnetic steel slot 12 along the rotor core is 0°≤α≤40°, meaning that the angle α can range from 0° to 40°. As shown in Figures 9-10, within this range, the average torque of the motor decreases slightly, but the torque ripple decreases rapidly. This is particularly applicable to motors with five pole pairs, i.e., ten main permanent magnets 2.

[0054] In this embodiment of the present application, the auxiliary permanent magnet module further includes a second auxiliary permanent magnet unit located between the first auxiliary permanent magnet unit. The angle α formed between the magnetization direction of the second auxiliary permanent magnet unit and the radial centerline of the second magnetic steel slot along the rotor core is 0. The number of second auxiliary permanent magnet units is not limited and can be one or more.

[0055] As shown in FIG3 , in another embodiment of the present application, the auxiliary permanent magnet module 3 includes a first auxiliary permanent magnet unit 311 and a first auxiliary permanent magnet unit 312, and a second auxiliary permanent magnet unit body 313 located between the first auxiliary permanent magnet unit 311 and the first auxiliary permanent magnet unit 312. The magnetization direction of the second auxiliary permanent magnet unit 313 coincides with the radial centerline A of the second magnetic steel slot 12 along the rotor core 1, and the angle formed by the two is 0. In this embodiment, the second auxiliary permanent magnet unit 313 includes one second auxiliary permanent magnet unit. In other embodiments, the second auxiliary permanent magnet unit may also include two or more second auxiliary permanent magnet units, in which case the magnetization direction of the two or more second auxiliary permanent magnet units and the radial centerline A of the second magnetic steel slot 12 along the rotor core form an angle of 0. In the embodiment of the present application, the distribution of the auxiliary permanent magnet modules 3 is symmetrical about the radial center line of the second magnetic steel slot 12 along the rotor core 2, and the angle α of each auxiliary permanent magnet unit (the first auxiliary permanent magnet unit and / or the second auxiliary permanent magnet unit) located on one side of the center line decreases from the side away from the center line A to the side close to the center line A. As shown in Figure 4, in another embodiment of the present application, the at least two first auxiliary permanent magnet units include four first auxiliary permanent magnet units (314, 315, 316, 317). The first auxiliary permanent magnet unit 314 and the first auxiliary permanent magnet unit 315 are symmetrical with the first auxiliary permanent magnet unit 316 and the first auxiliary permanent magnet unit 317 about the center line A of the second magnetic steel slot along the radial direction of the rotor core. Taking the first auxiliary permanent magnet 314 and the first auxiliary permanent magnet 315 located on one side of the center line A as an example, the angle α1 formed by the magnetization direction of the first auxiliary permanent magnet unit 314 and the center line of the second magnetic steel slot 12 along the radial direction of the rotor core is smaller than the angle α2 formed by the opposite direction of the magnetization direction of the first auxiliary permanent magnet unit 315 and the center line A of the second magnetic steel slot 12 along the radial direction of the rotor core, that is, 0≤α1<α2≤90.

[0056] As shown in FIG2 , in one embodiment, the length L2 of the auxiliary permanent magnet module 3 along the radial direction of the rotor core 1 is less than the length L1 of the main permanent magnet 2 along the radial direction of the rotor core 1, that is, 0 < L2 / L1 < 1. In another embodiment, 0.1 ≤ L2 / L1 ≤ 0.5. The main permanent magnet 2 is effectively divided into two parts, one of which is arranged adjacent to the auxiliary permanent magnet module 3, so that the magnetic flux of this part is connected in series with the auxiliary permanent magnet module 3 and enters the air gap 202; the other part is closer to the air gap 202, and the solid structure of the rotor core 1 is between two adjacent auxiliary permanent magnet modules 3. This reduces the proportion of openings on the rotor core 1, ensures the strength of the rotor core 1, and avoids the phenomenon of magnetic circuit saturation and magnetic flux density reduction.

[0057] In one embodiment, the auxiliary permanent magnet module 3 is disposed near the inner edge of the rotor core 1. The sidewalls of the auxiliary permanent magnet module 3 near the inner edge of the rotor core and the sidewalls of the main permanent magnet 2 near the inner edge of the rotor core are located on the same circumference with the axis of the rotor core 1 as the center. That is, multiple auxiliary permanent magnet modules 3 are distributed along the circumference of the rotor core 1. The auxiliary permanent magnet modules 3 are disposed near the rotor axis, which is equivalent to the auxiliary permanent magnet modules 3 being disposed at the magnetic leakage point of a traditional strip-shaped rotor core 1. The magnetic poles on both sides of the main permanent magnet 2 are the same as the magnetic poles on the outside of the auxiliary permanent magnet module 3, thereby expanding the area with more magnetic lines of force, enhancing the magnetic density of the air gap 202, and reducing internal magnetic leakage. As shown in FIG1 , the materials of the main permanent magnet 2 and the auxiliary permanent magnet module 3 can be neodymium iron boron or ferrite. The main permanent magnet 2 has a rectangular cross-section, and the magnetization direction is parallel to the tangent direction of the rotor core 1. In the adjacent main permanent magnets 2 and auxiliary permanent magnet modules 3, the side of the main permanent magnet 2 facing the auxiliary permanent magnet 3 is parallel to or in contact with the side of the auxiliary permanent magnet 3 facing the main permanent magnet 2. For example, the overall shape of each auxiliary permanent magnet module 3 in the second magnetic steel slot 12 can be roughly fan-shaped, such as a standard fan-shaped or a fan-shaped with curved inner and outer side walls, so that the overall spacing between the auxiliary permanent magnet module 3 and the main permanent magnet 2 is uniform, thereby better enhancing the main magnetic circuit flux and reducing magnetic leakage near the rotor shaft. It can be understood that the materials and shapes of the above-mentioned main permanent magnets 2 and auxiliary permanent magnet modules 3 are only examples, and this application does not limit the materials and shapes of the main permanent magnets 2 and auxiliary permanent magnets 3.

[0058] In a specific embodiment, as shown in Figures 2 and 3, the distance between the side of the main permanent magnet 2 facing the auxiliary permanent magnet module 3 and the side of the auxiliary permanent magnet module 3 facing the main permanent magnet 2 is D, 0≤D≤0.5mm. Specifically, the distance D between the side of the main permanent magnet 2 facing the auxiliary permanent magnet 3 and the side of the auxiliary permanent magnet 3 facing the main permanent magnet 2 is as small as possible, thereby better enhancing the main magnetic circuit flux and reducing magnetic leakage near the rotor shaft.

[0059] In one embodiment, as shown in Figures 6-7 , the rotor core 1 includes a plurality of stacked first silicon steel sheets 13, through which the main permanent magnets 2 and the auxiliary permanent magnet modules 3 pass. The first silicon steel sheets 13 are provided with a plurality of first through-slots 131 and a plurality of second through-slots 132. The first through-slots 131 of the plurality of first silicon steel sheets 13 are sequentially connected to form first magnetic steel slots 11, and the second through-slots 132 of the plurality of first silicon steel sheets 13 are sequentially connected to form second magnetic steel slots 12. In other words, the rotor core 1 can be formed by stacking a single type of silicon steel sheets and secured by fasteners. A solid iron core structure separates the auxiliary permanent magnet modules 3 from the main permanent magnets 2, and separates the permanent magnets (the auxiliary permanent magnet modules 3 and the main permanent magnets 2) from the rotor shaft. This sacrifices some magnetic flux linkage, reduces the complexity of the rotor core 1, and improves its structural strength.

[0060] In one embodiment, the rotor core 1 includes a plurality of stacked first silicon steel sheets 13, with at least one second silicon steel sheet 14 stacked between at least two adjacent first silicon steel sheets 13. The main permanent magnets 2 and the auxiliary permanent magnet modules 3 both pass through the first and second silicon steel sheets 13, and the second silicon steel sheets 14 have a hollow portion 141. Each main permanent magnet 2 and each auxiliary permanent magnet module 3 is at least partially located within the hollow portion 141. The first silicon steel sheets 13 are defined with a plurality of first through-slots 131 and a plurality of second through-slots 132. The first through-slots 131 of the plurality of first silicon steel sheets 13 are correspondingly arranged to form the first magnetic steel slots 11, and the second through-slots 132 of the plurality of first silicon steel sheets 13 are correspondingly arranged to form the second magnetic steel slots 12. The main permanent magnets 2 and the auxiliary permanent magnet modules 3 both pass through the second silicon steel sheets 14. The second silicon steel sheets 14 have a hollow portion 141. Each main permanent magnet 2 and each auxiliary permanent magnet module 3 is at least partially located within the hollow portion 141. Due to the presence of the hollow portion 141 in the second silicon steel sheet 14, there is no solid iron core structure separating the auxiliary permanent magnet module 3 from the main permanent magnet 2, and between the permanent magnets (the auxiliary permanent magnet module 3 and the main permanent magnet 2) and the rotor shaft. This can further reduce magnetic flux leakage, improve the motor's back EMF and torque, power density, and permanent magnet utilization. In this example, the rotor core 1 is made of two types of silicon steel sheets mixed and alternately laminated in a proportional manner. The second silicon steel sheet 14 eliminates part of the solid iron core structure between the auxiliary permanent magnet module 3 and the main permanent magnet 2, as well as the solid iron core structure between the permanent magnet and the outside of the rotor shaft, further reducing magnetic leakage, thereby improving the utilization of the permanent magnets and the power density of the motor. The first silicon steel sheet 13 supports the main permanent magnet 2, the auxiliary permanent magnet module 3, and the connection between the rotor core 1 and the rotor shaft.

[0061] In one embodiment, the second silicon steel sheet 14 is provided with a plurality of first limiting grooves 142 and a plurality of second limiting grooves 143 at intervals along the edge of the hollow portion 141. The plurality of first limiting grooves 142 are provided in the same number as the plurality of first through-grooves 131 and are provided in a one-to-one correspondence, and the plurality of second limiting grooves 143 are provided in the same number as the plurality of second through-grooves 132 and are provided in a one-to-one correspondence. Both the first limiting grooves 142 and the second limiting grooves 143 are communicated with the hollow portion 141. One end of the main permanent magnet 2 is inserted into the first limiting groove 142 and partially located within the hollow portion 141, while one end of the auxiliary permanent magnet module 3 is inserted into the second limiting groove 143 and partially located within the hollow portion 141. The second silicon steel sheet 14 cooperates with the main permanent magnet 2 through the first limiting groove 142 and with the auxiliary permanent magnet module 3 through the second limiting groove 143, thereby limiting the main permanent magnet 2 and the auxiliary permanent magnet module 3.

[0062] In the present application, the rotor core 1 can be formed entirely of first silicon steel sheets 13 stacked together; alternatively, the rotor core 1 can be formed by alternating one first silicon steel sheet 13 and one second silicon steel sheet 14, or by alternating two first silicon steel sheets 13 and three second silicon steel sheets 14. The present application does not limit the ratio of the alternating arrangement of the first silicon steel sheets 13 and the second silicon steel sheets 14.

[0063] The first silicon steel sheet 13 and the second silicon steel sheet 14 are both provided with mounting holes 15. The fasteners can be rivets or bolts. The first silicon steel sheet 13 and the second silicon steel sheet 14 are aligned, and the fasteners are passed through the mounting holes 15 on the first silicon steel sheet 13 and the second silicon steel sheet 14 in sequence to lock them, thereby ensuring the stacking coefficient of the rotor core 1 and the structural strength of the rotor.

[0064] As shown in Figures 1, 2, and 8, in one embodiment, grooves 16 are formed on the outer edge of the rotor core 1, corresponding to each main permanent magnet 2. These grooves 16 are not connected to the corresponding first magnetic steel slots 11. In other words, the end of the first magnetic steel slot 11, away from the axis of the rotor core 1, is closed, reducing the risk of the main permanent magnet 2 being ejected during high-speed rotation. Furthermore, the presence of grooves 16 creates a non-uniform air gap 202 between the outer edge of the rotor core 1 and the inner edge of the stator, reducing torque fluctuations.

[0065] Based on the above embodiment, the groove 16 is arranged to gradually expand as it approaches the outer edge of the rotor core 1, and the inner wall of the groove 16 smoothly transitions into the outer edge of the rotor core 1. This results in the air gap 202 formed between the outer edge of the rotor core 1 and the inner edge of the stator exhibiting a gradual trend of first increasing and then decreasing, with a smooth transition. This prevents abrupt changes in the air gap 202 from causing additional torque fluctuations.

[0066] In one example, the outer edge of the rotor core 1 is composed of multiple arc segments, forming a groove 16 structure, as shown in Figure 1, with the rotor center at O1. Taking the right side of the centerline as an example, the first arc segment is the arc to the right of point Q, centered at the rotor center O1 and with a radius of R1. The arc segment to the left of point Q is centered at O2 and has a radius of R2. O1 and O2 do not overlap, and R2 is smaller than R1. The two arc segments form a non-uniform air gap 202, effectively reducing torque ripple.

[0067] In addition, as shown in FIG8 , the present application further provides a motor, comprising a stator assembly 201 and the motor rotor 100 as described above, wherein the stator assembly 201 is sleeved around the motor rotor 100. Since the motor comprises the motor rotor 100 as described above, the motor has all the beneficial effects of the motor rotor 100, which will not be described in detail here.

[0068] The following table compares the torque performance of the rotor core 1 topology and the traditional banner topology in one embodiment of the present application. The two have the same stack thickness, air gap and other dimensions, use the same rotor core and permanent magnet materials, and have the same winding distribution, wire diameter, and number of turns. The only change is in the rotor topology. When the angle α between the magnetizing direction of the auxiliary permanent magnet module 332 and the radial centerline of the second magnetic steel slot along the rotor core is 30°, it can be seen that compared with the traditional banner motor, the motor torque / power density proposed in the embodiment of the present application can be increased by 21.65%, and the torque ripple can be reduced by 2.1%. The topology scheme combining the banner type and the auxiliary permanent magnet module 3 proposed in this application can effectively improve the torque / power density of the motor and reduce torque ripple.

[0069] Average torque / NmTorque fluctuation peak-to-peak value / NmTorque fluctuation value / %Traditional banner type 1.1990.0504.20%Main permanent magnet plus auxiliary permanent magnet module 1.4580.0312.10%

[0070] Figure 9 is a comparison diagram of the absolute value of the core magnetic flux density of the topology combining the banner type and auxiliary permanent magnet module (main magnet 2 and auxiliary permanent magnet module 3) proposed in this application and the traditional banner type (only main permanent magnet) topology at a vertical distance H of 1 mm from the edge of the first magnetic steel slot 11 and the second magnetic steel slot 12 on one side close to the rotor shaft (the vertical distance H is shown in combination with Figures 2 and 3). It can be found that the topology proposed in this application can effectively reduce the leakage flux near the rotor shaft of the traditional banner type motor, thereby increasing the effective magnetic flux, which helps to improve the back electromotive force and torque / power density of the motor 200.

[0071] Figure 10 is a graph showing the relationship between the angle α between the magnetizing direction of the auxiliary permanent magnet module 3 and the radial center line A of the second magnetic steel slot 12 along the rotor core 1 and the torque performance of the motor. The range of the angle α is [0°, 90°]. Within this range, as the angle α increases, the average torque of the motor 200 gradually decreases, and the torque fluctuation of the motor 200 first decreases and then increases. The trend of the change in the torque performance of the motor 200 shows that there is an optimal value for the angle α for different torque performance requirements. For example, under the condition that the average torque meets the requirements, the torque fluctuation can be quickly reduced by optimizing the magnetic flux distribution through a reasonable angle α value. The angle α ranges from 0° to 40°, which is particularly suitable for a rotor core when the number of pole pairs of the motor 200 is 5 pairs, that is, when the number of main permanent magnets 2 is 10.

[0072] The above description is merely an embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made using the contents of the present application specification and drawings under the inventive concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A motor rotor, wherein: The motor rotor comprises a rotor core, the rotor core has a plurality of first magnetic steel slots evenly distributed along the circumference of the rotor core, the first magnetic steel slots extend radially and are provided with tangentially magnetized main permanent magnets; a second magnetic steel slot is further provided between any two adjacent first magnetic steel slots on the rotor core, an auxiliary permanent magnet module is provided in the second magnetic steel slot, the auxiliary permanent magnet module comprises at least two first auxiliary permanent magnet units, and the closest surface magnetic poles of any two adjacent main permanent magnets are the same; The magnetization direction of the first auxiliary permanent magnet unit includes a radial magnetization component; the direction of the radial magnetization component of the first auxiliary permanent magnet unit located between the two main permanent magnets with opposite magnetization directions points to the stator along the radial direction of the rotor core; the direction of the radial magnetization component of the first auxiliary permanent magnet unit located between the two main permanent magnets with opposite magnetization directions points to the rotor axis along the radial direction of the rotor core; The magnetization direction of the first auxiliary permanent magnet unit includes a tangential magnetization component, and the tangential magnetization component of the first auxiliary permanent magnet unit is the same as the magnetization direction of the main permanent magnet close to the first auxiliary permanent magnet unit, wherein the magnetization direction of the main permanent magnet and the tangential magnetization direction of the first auxiliary permanent magnet unit are both tangential directions of a circle with the axis of the rotor core as the center.

2. The motor rotor according to claim 1, wherein: The at least two first auxiliary permanent magnet units include at least two auxiliary permanent magnets having at least one magnetization direction or one auxiliary permanent magnet having at least two magnetization directions.

3. The motor rotor according to claim 1, wherein: The angle between all magnetizing directions / the opposite directions of magnetizing directions in the auxiliary permanent magnet module and the center line of the second magnetic steel slot along the radial direction of the rotor core is α; wherein 0°≤α≤90°.

4. The motor rotor according to claim 2, wherein: The angle between all magnetizing directions / the opposite directions of magnetizing directions in the auxiliary permanent magnet module and the center line of the second magnetic steel slot along the radial direction of the rotor core is α; wherein 0°≤α≤40°.

5. The motor rotor according to claim 2, wherein: The distribution of the auxiliary permanent magnet modules is symmetrical about the second magnetic steel slots along the radial center line of the rotor core, and the angle α of each of the first auxiliary permanent magnet units located on one side of the center line decreases from the side away from the center line to the side close to the center line.

6. The motor rotor according to claim 1, wherein: The auxiliary permanent magnet module further includes a second auxiliary permanent magnet unit located in the middle of the first auxiliary permanent magnet unit, and an angle α between a magnetization direction of the second auxiliary permanent magnet unit and a center line of the second magnetic steel slot along the radial direction of the rotor core is 0.

7. The motor rotor according to claim 1, wherein: The auxiliary permanent magnet module is arranged close to the inner edge of the rotor core.

8. The motor rotor according to claim 7, wherein: The side wall of the auxiliary permanent magnet module close to the inner edge of the rotor core and the side wall of the main permanent magnet close to the inner edge of the rotor core are located on the same circumference with the axis of the rotor core as the center.

9. The motor rotor according to claim 1, wherein: The length of the auxiliary permanent magnet module along the radial direction of the rotor core is L2, and the length of the main permanent magnet along the radial direction of the rotor core is L1, wherein 0<L2 / L1<1.

10. The motor rotor according to claim 9, wherein: 0.1≤L2 / L1≤0.

5.

11. The motor rotor according to claim 1, wherein: In the adjacent main permanent magnet and auxiliary permanent magnet modules, a side surface of the main permanent magnet facing the auxiliary permanent magnet module and a side surface of the auxiliary permanent magnet facing the main permanent magnet module are arranged in parallel or in close contact.

12. The motor rotor according to claim 1, wherein: A distance between a side surface of the main permanent magnet facing the auxiliary permanent magnet module and a side surface of the auxiliary permanent magnet module facing the main permanent magnet is D, and 0≤D≤0.5 mm.

13. The electric machine rotor according to any one of claims 1 to 12, wherein: The rotor core comprises a plurality of stacked first silicon steel sheets, and the main permanent magnet and the auxiliary permanent magnet module both pass through the first silicon steel sheets; And / or, the rotor core includes a plurality of stacked first silicon steel sheets, with at least one second silicon steel sheet stacked between at least two adjacent first silicon steel sheets; the main permanent magnet and the auxiliary permanent magnet module both pass through the first silicon steel sheet and the second silicon steel sheet, and the second silicon steel sheet has a hollow portion, and the main permanent magnet and the auxiliary permanent magnet module are at least partially located in the hollow portion.

14. A motor, wherein: The motor comprises a stator assembly and a motor rotor as claimed in any one of claims 1 to 13, wherein the stator assembly is sleeved on the periphery of the motor rotor.

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